Abrasion or friction induced wear in fabrics created by motion both during wear and in the laundering process is an important feature in the ageing of garments. This is evidenced by a progressive reduction in the mechanical strength of fabric measured by, for example, the tensile strength of a test strip. In extreme cases, this wear finally results in the actual teasing of cloth. Visually, areas of garments subjected to relatively extreme abrasion such as cuffs or collars can develop signs of wear which very obviously detract from the appearance of clothing.
It is known that the regular use of fabric softeners using various quaternary ammonium moieties can mitigate friction-induced wear (WO 97/36976). Without being bound by theory, it is believed that this is achieved by a lubrication of fibres and a consequent raising of the resistance of the cloth to abrasional wear and tear. Efforts to extend this protection by using higher levels of softener are impractical from both cost and technical perspectives e.g. fabric water proofing, discolouration, unpleasant hand feel etc. Accordingly, there is a need for additives or adjuncts to state of the art softener formulations which will boost their power to resist frictional wear without the aforementioned drawbacks.
As given above one component of the compositions of the present invention are polyorganosiloxanes. Such compounds are known to be used on an industrial scale to finish fabrics by providing them with a permanent or semi-permanent finish aimed at improving their general appearance. Significant for these industrial fabric finishing processes is a co-called curing step generally involving temperatures in excess of 150° C. often for periods of one hour or more. The object here is to form a chemical finish which resists destruction during subsequent cleaning/laundering of fabrics. This process of finishing is not carried out in domestic applications and accordingly one would not expect benefits of a comparable nature or magnitude from polyorganosiloxanes included as adjuncts in domestic softeners. Indeed, it is noteworthy that if the compounds of the current invention achieved a permanence associated with industrial textile finishing, problems associated with a cumulative build through the wash cycles could occur such as fabric discoloration and even in extremes an unpleasant feel to the wearer.
Surprisingly, it has been found that the use of selected polyorganosiloxanes, or mixtures thereof, together with selected additives in fabric softener compositions provide excellent abrasion resistance effects when applied to fabrics during a textile laundry operation.
Similar benefits are noted when compositions of the current invention are incorporated into tumble dryer additives such as impregnates on sheets.